Slotting segments with v-shaped cutting portion for corrugated paperboard and the like



May 29, 1962 w. M. WILCOX 3,036,486

SLOTTING SEGMENTS WITH V-SHAP CUTTING PORTION FOR CORRUGATED PAPERBOARND THE LIKE Filed March 7, 1958 Izwezzimfl:

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by 8, 92 0W, *H/W ate dfidfiA d Patented May 29, 1962 ffice 3,636,486SLOTTENG SEGMENTS WETH V -SHAfEl) CUTTENG PORTKON FOR CORRUGATEDPAPEOARD AND THE LlKlE Walter M. Wilcox, Westminster, Mass, assignor toSimonds Saw and Steel Company, Fitchburg, Mass., a corporation ofMassachusetts Filed Mar. 7, 1958, Ser. No. 719,872 3 Claims. (ill.83-671) This invention relates to slotting equipment for cutting slotsin compressible sheets such as corrugated paperboard used in thecorrugated container industry, as Where carton tops are to be folded orwhere partition inserts for separating bottles, cans or the like areslotted to overlap.

Due to the compressible nature of such corrugated and laminatedpaperboard difficulty is experienced in slotting it on rotary machines,with frequently resultant objectionable tearing, compression andirregular deformation along one or both side walls of the desired slot.

The similar slotting irregularities are experienced in greater or lessdegree with the various constructions of corrugated paperboard, whethersingle or double faced, or of relatively heavy or light weights andgrades of paper, or with one or a plurality of the fluted strata, orwith the fluting of one or another form as to steepness and pitch. Ingeneral, the softer the paperboard, in the sense of yielding underlateral pressure, the greater the difficulty in effecting acceptablyregular slotting.

Accordingly the present invention aims to provide im proved slot-cuttinginstrumentalities herein termed slotting segments, for rotary slottingmachines for paperboard and the like, and which are adapted for bettercoaction with the opposed rotary cutter elements in such machines so asto afford more regular and generally improved slot formation.

In the drawings illustrating by way of example one em" bodiment of theinvention:

FIG. 1 shows in side elevation a slotter assembly of a standard orpreferred machine for feeding and acting on corrugated paperboardblanks, with the supporting arbors in cross-section, including an upperarbor mounting a holder equipped with the slotting segments of theinvention and a lower arbor carrying the cooperating pair of spacedcutter discs;

FIG. 2 is a corresponding view at right angles to FIG. 1;

FIG. 3 shows an assembly of slotting segments of the invention upon alarger scale;

FIG. 4 is a cross-sectional view through one such segment, upon a stilllarger scale;

FIG. 5 is a fragmentary enlargement corresponding to a central portionof FIG. 2 illustrating the slotting action; and

FIG. 6 is a diagrammatic view of a portion of a corrugated paperboardblank for a box or carton typical of the products with which theinvention is concerned.

With further reference to the drawings, FIGS. 1 and 2 illustrate thesegmental slotting means of the invention in use at a slotting stationof the usual or preferred machine for acting upon corrugated paperboardand the like compressible r heets to be slotted, as in the manufactureof boxes and cartons. Such station is generally defined by spacedparallel arbors 7 and 3, herein called upper and lower merely foridentification. It will be understood that the sheets or blanks S of thepaperboard are advanced along a generally horizontal path between thearbors as by rotary feed means not shown and whereby the blanks arepresented in appropriately spaced and timed relation for slotting at thedesired areas.

One of the arbors, herein the upper arbor 7, carries a disc-like holderor spider 9 in which the segmental circular cutter device of theinvention is mounted as by means of bolts 11 adjustably receivable inar-cuate slots 12 of the holder. The other or lower arbor 8 has fixed onit a pair of square-edged or slightly concaved rotary cutters 15, 15spaced and aligned to receive between them the segmental cutter means tobe described.

One unit of the segmental slotting means of the invention is designatedas a whole at 20. It has an angular extent corresponding to the lengthof the particular slot to be formed, as for example a segment in theillustrated example. Such unit 20 may comprise a single arouate piece,whether for relatively short slots or in any case. For adaptability todifferent lengths of slots, it conveniently is made up of a plurality ofsegmental portions such as herein shown at 21, 22, 23. These are madeavailable in different angular lengths adapted to be combined to provideslotting units of a total length as appropriate to the given work. Forexample in the instance shown there is an intermediate segment 22 ofabout 50 and two end segments of about 20 each, together furnishing theapproximate 90 of segmental cutter unit desired in this case. Obviouslythe unit for the particular slotting requirement may be assembled fromother lengths of segments, such as three 30 segments for a 90 unit, two50 and one 20 segment for a unit, or four 30 segments for such latterunit, to mention but a few examples. Thus the segments may be suppliedin appropriate angular lengths for production of whatever length ofslotting is likely to be required.

In the illustrated example the segment unit 20 is assumed to be forslots let into an edge portion of the paperboard blanks, such forexample as diagrammed at S in FIG. 6, the slots s accordingly having oneend upon. The trailing slotter segment such as the member 23 herein hasat the terminal edge a projection 24 with transverse cutting edge forcontacting with the adjacent end of the scrap cut from the slot and forforming the closed end of the slot. It will be understood that in thecase of slots other than at the edge of a blank and hence closed at bothends a similar projection is provided at the leading edge of the leadingsegment such as 21 hereof. Each segment member 21, 22, 23 has one ormore mounting formations for cooperation with the holder 10 and bolt andslot means 11, 12, such as the bolt-receiving apertures 20 of preferredclosed or open elongate form.

Heretofore the slotting of corrugated paperboard has been in the natureof a punching action performed by a substantially blunt-corneredsegmental rotary plate element operating in opposition to square-edgedcutters generally like those at 15, 15 herein. Such prior segmentalelements have substantially solid circumferentim portions with theperipheral face substantially flat or slightly concaved and providingblunt punch-like opposed corner zones for punchshearing coaction withthe opposed rotary disc pair.

In contrast to such prior practice the present invention providesslotting segments adapted to have in coaction with the opposed pair ofsheet-supporting rotary members a rotary knife-cutting or slicing actionwhereby the resulting slots have clean straight side edges,substantially free of tearing or other irregularities and with minimumdeformation of the adjacent blank material.

Accordingly, as best seen in FIGS. 4 and 5, the segmental elements suchas 21, 22, 23 of the illustrated unit 20 are novelly fashioned along theouter circumference to present in effect a pair of sharp knife-edgelineal cutters 25, 25 having the cutting edges substantially in theplane of the side faces of the segment. Each such cutter 25 is definedbetween the adjacent side face of the segment and an inner face 26, 26disposed at an acute angle, preferably not more than about 20 to 25 tothe plane of the segment side wall and to the medial plane of thesegment. Such inner walls 26 of the respective cutters 25, 25 areoppositely and inwardly inclined, defining between them a steep-walledgroove of general V-form and preferably somewhat rounded at the bottom27 where these opposed inner walls intersect in the region of the medialplane of the segment. As shown the inner walls 26 are continuousuninterrupted planar surfaces but may be stepped or otherwise formed solong as they are symmetrically oppositely disposed to provide betweenthem a channel of a depth at least approximating that of the sheet orpaperboard to be slotted, and forming at their outer junctures with theside walls of the segments: of the thin-knife-edged cutters proper suchas 25. {In the illustrated example such channel has the form of a narrowdeep V-groove with the walls 26, 26 thereof presenting between them anangle of approximately 45 One or more of the mounting formations such asthe apertures 29, FIGS. 3 and 4, are provided in appropriate location oneach plate or segment such as 21, 22, 23 of each segmental slotting unit20, 'for cooperation with the nut and bolt or other fastener means 11 ofthe rotary holder 9. Such mounting formations 29 may be more or lesselongate radially of the segments and may extend in from the innermargins of the segments -for adjustment and adaptability to varioussupporting holders.

In operation at the cutting station the knife-edge cutters 25, 25 slicethrough the plural layers of the sheet or blank S along spaced linescleanly defining the sides or" a slot s. As represented in FIG. 5 thematerial at the respective outer sides of the cutter receives little orno compressive deformation. The scrap sc cut from the slot is in efiectstraddled by and largely received between the cutters 25, 25 or may insome part enter the underlying space between the lower rotary members15, 15. It is usually freed from the slot under the cross-cutting actionof the terminal projection 24. Stripper means such as fingers (notshown) in the scrap path may if desired be provided to deflect the scrapand assist in clearing it from the cutters and the sheet.

My invention is not limited to the particular embodiments thereofillustrated and described herein, and I set forth its scope in myfollowing claims.

I claim:

'1. For slotting corrugated paperboard and the like plural laminarcomposite paper webs, a slotting segment comprising a metal plate witharcuate outer margin described about a central axis of rotary support,the plate having a formation for mounting it on a rotary holderconcentric with such axis, said outer margin of the plate fashioned topresent in substantially the planes of the plate side faces a pair ofknife-edge arcuate cutters transversely spaced by the width of the slotto be formed, each said knife-edge cutter comprising an outer side facecoplanar with one side face of the segment plate and an inclined innerface at a small acute angle of not more than about 25 to the outer sideface and to the medial radial plane of the segment plate, said angularinner faces of the cutter pair being oppositely and symmetricallydisposed with respect to and converging inwardly substantially to meetin said medial plane and presenting between them an angle ofapproximately relative to each other thereby defining between them asteep-walled V-groove of an open depth at least approximating that ofthe laminar paper web to be slotted and adapting the peripheralknifeedges of the cutters to cleanly slice with minimal compressiveaction through corrugated paperboard laminae along slot-defining spacedcutting lines to provide a cut scrap having smooth sidewalls wherebysaid scrap will be releasably carried by said angular inner faces of thecutter.

2. A slotting segment according to claim 1 wherein an end of the segmenthas a generally radial outward projection with a transverse cutting edgefor forming the corresponding end of a slot.

3. A slotting segment according to claim 1 wherein the bottom of theV-groove is rounded in the region of the medial plane of the segment.

References Cited in the file of this patent UNITED STATES PATENTS Re.19,059 Schillo Jan. 23, 1934 609,896 Morris Aug. 30, 1898 1,123,532Heynan Jan. 5, 1915 1,404,788 Moore Jan. 31, 1922 2,015,877 ThompsonOct. 1, 1935 2,117,220 Sieg May 10, 1938 2,808,106 Belton Oct. 1, 1957

